From NI-43-101, page 70:

"In addition, marketability issues are being addressed. Some metals are considered to be deleterious in antimony purchases. For example, most antimony smelters will not accept material that exceeds 0.5% combined lead and arsenic. Smaller amounts of selenium and bismuth also pose potential limitations and may invoke smelter penalties. Hence a broader suite of elemental information has been acquired during the exploration of what is basically an antimony-gold-arsenic system."

0.5% is 5000 ppm.

Now go to page 65 and look at the assay summaries for As (arsenic) and Pb (lead).

Read the report. Where there is a concern for arsenic (and it is a small percentage), there are material processing tests already performed to provide processing steps for the mill to deal with this small concern.